1. Field of the Invention
This invention relates to a method and an apparatus for slab width control and more particularly, to a method and apparatus for allowing a casting mold to produce a steel slab having a substantially constant width.
2. Discussion
Steel casting molds are normally adapted to receive molten metal and to use the metal to produce a continuous slab of steel. The slab is often cut into various lengths, each of which is used in the manufacture of diverse products. Each manufacturing process requires slab lengths of a constant and certain width.
These molds usually have means to control the output slab width, based on a desired slab width. Each slab width also requires a certain mold taper. That is, an initial mold width and taper, associated with the desired slab width, is usually set before the metal is poured and modified for different required slab widths. Casting parameter variations, such as temperature, line speed and ferrostatic pressure cause the mold to produce a portion of the slab having a different width, from that of the initially cast portion. Consequently, the produced slab is of a varying width.
This lack of slab width control is particularly troublesome in applications requiring long slab lengths of a relatively large width, where the actually produced slab has long lengths of a very small width. In this situation, most of the slab is wasted or used for an alternate application. Moreover, even if the produced slab has a wider than desired width, it still must be cut, or sized by strip mill edgers in order to ensure a constant slab width. The edgers are relatively inefficient and expensive. Moreover, many mills do not ever have the edger capacity to appropriately size the slabs. Therefore, these slabs cannot be processed unless the slabs are actually cut to size.